DE9013638U1 - Engine monitoring arrangement - Google Patents

Description

between operating voltage zero and operating current zero crossing is given to the logic part, which then selects a work program adapted to the respective load condition by comparison with a stored Fef ^i ■ zgrr'^e and controls the drive of the washing machine accordingly.

I According to the present invention, several control functions of a washing machine drive can be implemented with a lower I Aw.^and, in particular a standstill detection, a blockage protection, a jt 25 control of compliance with the specified washing speed and a

Unbalance control according to the invention by a speed sensor coupled to the asynchronous motor and at least one

Speed comparator for detecting and/or triggering a monitoring signal by comparing a corresponding reference speed signal in the logic part with the respective speed signal of the speed sensor; advantageous features &Idigr; embodiments of the invention are each subject of the sub-

|; claims.

I 35 The speed values determined by means of a speed sensor flanged to the rotor shaft of the three-phase motor are in I the value required to control the converter and in itself

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) 1 existing logic part with speed reference values that can be specified there and assigned to certain control functions and, if they coincide with the respective reference values, the corresponding protection or control functions are displayed or triggered.

The implementation of such other distributed embodiments of the invention are explained in more detail below using a schematically illustrated embodiment in the drawing.

A logic part, for example, containing a microcomputer, controls an asynchronous motor 1 from a single-phase supply R;S via a power supply unit 31, a pulse width modulator 32 and a driver output stage part 33 with a specific clock frequency according to a predetermined speed η and a predetermined speed direction η that changes in the reversing cycle.

A tachogenerator 2 is coupled to the rotor shaft of the asynchronous motor 1, which preferably consists of a stator-side Hall IC, in particular with a digital signal output, and a corresponding rotor-side magnet wheel. The actual speed values supplied by the tachogenerator 2 are given to four speed comparators 4 or 5 or 6 or 7 in the logic part 3. As further comparison values, various reference speed signals n=0 or nvO or ^■k ⁿ i or n^ n2 are given to the speed comparators 4 or 5 or 6 or 7 from a speed memory 34 in the logic part 3.

The logic part 3 with the comparators 4 or 5 or 6 or 7 is now programmed in such a way that when a speed n=0 is detected in the comparator 4, a standstill signal is sent from this to the connected display device 41; instead of the detection speed n=0, a speed η - η 0 can also be specified, the reference value of which is, however, lower than the reference value for the blocking or stiff case. When a speed η -r U is detected, the

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Comparator 5 generates a signal such that the blocking of the drive is indicated in the connected display device 51 and, if necessary, by simultaneously switching off the driver output stage part 33, a blocking protection for the motor operation is guaranteed.

In the comparator 6, a specific washing target speed n is detected, which is also stored as a reference speed signal in the logic part 3. By adjusting the pulse width

IG of the voltage signals supplying the asynchronous motor 1, a 'change in the mean value of the motor voltage and a speed correction in the sense of a constant target speed n, can be achieved, compliance with which can be observed in the display device 61 connected to the comparator 6.

In the speed comparator 7, a speed is detected which periodically deviates from a reference speed signal n ₂ also stored in the memory of the logic part 3. An imbalance can be detected in the device connected to the comparator 7. The display device 71 can be used to switch off the asynchronous motor 1 if the imbalance is too great by sending a corresponding signal to the driver output stage part 33.

Claims (7)

9063M 1OE Protection claims 1. Motor monitoring arrangement for a frequency-controlled, converter-fed asynchronous motor (1) with a squirrel-cage rotor, characterized by a speed sensor (tachogenerator 2) coupled to the asynchronous motor (1), at least one speed comparator (4 or 5 or 6 or 7) for detecting and/or triggering a monitoring signal by comparing a corresponding reference speed signal (n=0 or n-j>0 or n^n, or n^n^,) in the logic part (3) with the respective speed signal of the speed sensor (tachogenerator 2). 2 Motor monitoring arrangement according to claim 1, characterized by a speed sensor with a stator-side Hall IC, in particular with a digital signal output, and a corresponding rotor-side magnet wheel. 3. Engine monitoring arrangement according to claim 1 or 2, characterized by a standstill speed comparator (4). ix. Engine monitoring arrangement according to claim 1 or 2, characterized by a blocking speed comparator (5). 5. Engine monitoring arrangement according to claim 1 or 2, characterized by a constant speed speed comparator (6). 6. Engine monitoring arrangement according to claim 1 or 2, characterized by an unbalance speed comparator (7). 906 · 1 7. Engine monitoring arrangement according to one of claims 3 to 6, characterized by a display device (41 or 51 or 61 or 71) connected downstream of a speed comparator (4 or 5 or 6 or 7).